Chapter 3- Pearson

Chlamydia trachomatis elementary bodies measure approximately 0.25 micrometers in diameter. What is this measurement expressed in nanometers (nm)?

A. 250 nm

B. 25,000 nm

C. 2500 nm

D. 25 nm

E. 2.5 nm

A

A paramecium is approximately 150 micrometers in length. What is this measurement expressed in millimeters (mm)?

A. 0.015 mm

B. 1500 mm

C. 15 mm

D. 0.15 mm

E. 1.5 mm

D

Coarse focus knob

Focused for initial focusing; should never be used when the high-power objective lens or oil immersion objective lens is in place

Diaphragm

Controls how much light from the illuminator reaches the specimen

Objective Lens

Lens that is closest to the slide and provides initial magnification of a specimen

Condenser Lens

Used to focus the light from the illuminator onto the slide

Ocular Lens

Lens that you look through

Fine focus knob

Used after initial focusing to sharpen the image

Stage

Platform on which the slide is placed for viewing

Why is a specimen smaller than 200 nm not visible with a light microscope?

A. Visible light is only good at wavelengths below 390 nm.

B. The lenses only go to 100 X magnification power.

C. Anything smaller than 200 nm cannot interact with visible light.

D. It is too easy to lose on the stage.

A

What happens to the light rays when they hit the specimen?

A. They are reflected, refracted, or absorbed by the specimen.

B. They are diverted to the ocular lens.

C. They are focused into a small area towards the objective lens.

D. They are absorbed by the stage.

A

What is the role of the ocular lens?

A. To adjust the wavelength of light

B. To focus the light to a high intensity in a small area

C. To do the bulk of the magnification

D. To recreate the image in the viewer’s eye

D

What is meant by light rays being divergent?

A. It is heading upwards

B, It is coming together to a focused beam

C. It is spreading out

C

In a typical brightfield microscope (seen in the animation), at which point does magnification begin?

A. The ocular lens

B. The lamp

C. The objective lens

D. The stage

E. The condenser lens

C

Which microscope uses visible light?

A. fluorescence microscope

B. confocal microscope

C. scanning electron microscope

D. differential interference contrast microscope

E. scanning acoustic microscope

D

Which microscope achieves the highest magnification and greatest resolution?

A. darkfield microscope

B. phase-contrast microscope

C. fluorescence microscope

D. electron microscope

E. compound light microscope

D

Which of the following correctly traces the path of light through the compound microscope?

A. Condenser — light source — specimen — ocular lens — objective lens

B. Condenser — light source — specimen — objective lens — ocular lens

C. Light source — specimen — condenser — objective lens — ocular lens

D. Light source — condenser — objective lens — specimen — ocular lens

E. Light source — condenser — specimen — objective lens — ocular lens

E